The present invention relates to memory devices. In particular, a method for fabricating a memory device and a memory device structure using programmable resistance materials are described.
A variety of memory technologies used in integrated circuits employ metal oxides. Memory types that employ metal oxides include programmable metallization cells and resistive RAM, for example. Metal oxide based memory devices, including those using transition metal oxides, are expected to improve scalability of memory structures and their compatibility with conventional CMOS processing.
Techniques used to form metal oxides include deposition methods such as chemical vapor deposition (CVD), physical vapor deposition (PVD) or sputtering, atomic layer deposition (ALD), and others. These techniques invariably need precursors and specialized deposition equipment, which are usually costly and have high operation costs. Direct oxidation of an underlying metal has been used (for example, a rapid thermal oxidation using an oxidizing agent such as oxygen or nitrous oxide), which can require high temperatures, greater than 450 degrees Celsuis, and consume a large part of a “thermal budget” in manufacturing an integrated circuit.
It is desirable to provide metal oxide structures having improved quality, and which have a lower impact on the thermal budget in manufacturing.